Carbon nanotube gas sensor and method of manufacturing the same

Abstract

A carbon nanotube (“CNT”) gas sensor includes a substrate, an insulating layer formed on the substrate, electrodes formed on the insulating layer, and CNT barriers that protrude higher than the electrodes in spaces between the electrodes to form gas detecting spaces. A method of manufacturing the gas sensor includes forming an insulating layer on a substrate, forming an electrode pattern on the insulating layer, coating CNT paste having a thickness greater than a thickness of electrodes in the electrode pattern on the electrodes and the insulating layer, and patterning and firing the carbon nanotube paste, including using a photolithography method, to retain only portions of the CNT paste coated on spaces between the electrodes.

1. A carbon nanotube gas sensor comprising:
 a substrate; 
 an insulating layer formed on the substrate; 
 electrodes formed on a same plane of the insulating layer; and 
 carbon nanotube barriers, which
 protrude higher than the electrodes, and 
 are disposed in spaces between the electrodes; and 
 gas detecting spaces formed on the electrodes between the carbon nanotube barriers; wherein ends of the carbon nanotube barriers are exposed, and the carbon nanotube barriers each comprise a plurality of carbon nanotubes, a first organic polymer, and a different second organic polymer. 
 
 
     
     
       2. The carbon nanotube gas sensor of  claim 1 , wherein the carbon nanotube barriers have an initial resistance value of 100 kΩ or less, wherein the initial resistance is a resistance between the electrodes before a gas reaction. 
     
     
       3. The carbon nanotube gas sensor of  claim 2 , wherein sensitivity, defined as (final resistance−initial resistance)/initial resistance, is 100% or more, where the final resistance is a resistance between the electrodes after a gas reaction. 
     
     
       4. The carbon nanotube gas sensor of  claim 1 , wherein
 the substrate is formed of a transparent material, and 
 the electrodes are formed of a non-transparent material. 
 
     
     
       5. The carbon nanotube gas sensor of  claim 1 , wherein the electrodes have an inter-digitated shape structure in which the electrodes are separated from each other. 
     
     
       6. The carbon nanotube gas sensor of  claim 1 , further comprising a heater layer that heats the carbon nanotube barriers to reduce a recovery time. 
     
     
       7. The carbon nanotube gas sensor of  claim 1 , wherein the first organic polymer binds the carbon nanotubes and the electrodes, and the second organic polymer increases a sensitivity of the carbon nanotube barriers. 
     
     
       8. The carbon nanotube gas sensor of  claim 5 , wherein the electrodes have at least one first electrode and at least one second electrode which have a plurality of concave parts and convex parts, respectively. 
     
     
       9. The carbon nanotube gas sensor of  claim 8 , wherein the concave parts and the convex parts of the first electrode and the second electrode alternately face each other.